chore(server): Gracefully shutting down the server (#60)

Gracefully shutting down the server

cmd/summary/cmd_serve.go

@@ -2,6 +2,7 @@ package main
 
 import (
 	"context"
+	"errors"
 	"flag"
 	"fmt"
 	"log/slog"
@@ -99,7 +100,10 @@ func (s *serveCmd) Execute(ctx context.Context, f *flag.FlagSet, _ ...interface{
 
 	// Start the server in a goroutine, so we can listen for the context to be done.
 	go func(srv *http.Server) {
-		if err := srv.ListenAndServe(); err != nil {
+		err := srv.ListenAndServe()
+		if errors.Is(err, http.ErrServerClosed) {
+			slog.Debug("Server closed gracefully")
+		} else if err != nil {
 			slog.Error("Error serving requests", slog.String(logging.KeyError, err.Error()))
 		}
 	}(srv)

cmd/summary/main.go

@@ -3,7 +3,10 @@ package main
 import (
 	"context"
 	"flag"
+	"log/slog"
 	"os"
+	"os/signal"
+	"syscall"
 
 	"github.com/google/subcommands"
 )
@@ -24,6 +27,18 @@ func main() {
 	subcommands.Register(new(purgeCmd), "")
 
 	flag.Parse()
-	ctx := context.Background()
+
+	// Listen for ctrl+c and kill signals
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	go func() {
+		sig := make(chan os.Signal, 1)
+		signal.Notify(sig, os.Interrupt, syscall.SIGTERM)
+		got := <-sig
+		slog.Debug("Received signal, shutting down", slog.String("signal", got.String()))
+		cancel()
+	}()
+
 	os.Exit(int(subcommands.Execute(ctx)))
 }

pkg/dataaccess/db_mongo.go

@@ -25,7 +25,7 @@ func connectMongoDB(ctx context.Context) {
 		slog.Debug("Found MongoDB URI in environment")
 	} else {
 		// Missing environment variable.
-		slog.Error("No MongoDB URI provided in environment")
+		slog.Error(fmt.Sprintf("No %s environment variable provided", envDbConnStr))
 		os.Exit(1)
 	}
 

pkg/dataaccess/db_mysql.go

@@ -21,7 +21,7 @@ func connectMysql() {
 		slog.Debug("Found MySQL URI in environment")
 	} else {
 		// Missing environment variable.
-		slog.Error("No MongoDB URI provided in environment")
+		slog.Error(fmt.Sprintf("No %s environment variable provided", envDbConnStr))
 		os.Exit(1)
 	}